Antioxidant and free radical scavenging activities of edible weeds

Reactive oxygen species (ROS) such as superoxide anions, hydrogen peroxide, and hydroxyl, nitric oxide radicals, play an important role in oxidative stress related to the pathogenesis of various important diseases. Active (or reactive) oxygen species and free radical-mediated reactions are involved in degenerative or pathological processes. Antioxidants act as a major defense against radical mediated toxicity by protecting against the damages caused by free radicals. Antioxidant-based drugs/formulations for the prevention and treatment of complex diseases like atherosclerosis, stroke, diabetes, Alzheimer′s disease, and cancer have appeared during the last three decades. This has attracted a great deal of research interest in natural antioxidants. Flavonoids and phenolic compounds widely distributed in plants which have been reported to exert multiple biological effect, including antioxidant, free radical scavenging abilities, anti-inflammatory and anticarcinogenic activities. Recently there has been an upsurge of interest in the therapeutic potentials of medicinal plants as antioxidants in reducing such free radical induced tissue injury. The aim of the present investigation was to evaluate in vitro antioxidant and free radicals scavenging effect of two edible weeds. Certain weeds are nutritious and eaten as foods or vegetables. In the present study two weeds namely Chenopodium album and Vitis trifolia have been screened for their antioxidant potential by using various in vitro methods. Aqueous leaf extract Chenopodium album and methanolic fruit extract of Vitis trifolia exhibit significant reducing power and free radical scavenging effect on DPPH, hydroxyl, superoxide, hydrogen peroxide radicals. The extracts also inhibit nitric oxide production. All these antioxidant activities were concentration dependent which were compared with standard antioxidants such as BHA, á-tocopherol and ascorbic acid. In addition, total phenolic and total flavonoids contents were determined as gallic acid and catechin equivalents respectively. From the results, C. album leaf extract was found to contain 0.94 % total phenolic contents (gallic acid equivalent) and 0.27 % total flavonoid contents (catechin equivalent). Whereas V. trifolia fruit extract was found to contain 1.23 % phenolic compounds as gallic acid equivalent (GAE) and 0.38 % flavonoid content as catechin equivalent (CE).